/*
* Copyright (c) 2004 David Flanagan. All rights reserved.
* This code is from the book Java Examples in a Nutshell, 3nd Edition.
* It is provided AS-IS, WITHOUT ANY WARRANTY either expressed or implied.
* You may study, use, and modify it for any non-commercial purpose,
* including teaching and use in open-source projects.
* You may distribute it non-commercially as long as you retain this notice.
* For a commercial use license, or to purchase the book,
* please visit http://www.davidflanagan.com/javaexamples3.
*/
package je3.rmi;
import java.rmi.*;
import java.util.List;
/**
* This class is a placeholder that simply contains other classes and
* for interfaces remote banking.
**/
public class Bank {
/**
* This is the interface that defines the exported methods of the
* bank server.
**/
public interface RemoteBank extends Remote {
/** Open a new account, with the specified name and password */
public void openAccount(String name, String password)
throws RemoteException, BankingException;
/** Close the named account */
public FunnyMoney closeAccount(String name, String password)
throws RemoteException, BankingException;
/** Deposit money into the named account */
public void deposit(String name, String password, FunnyMoney money)
throws RemoteException, BankingException;
/** Withdraw the specified amount of money from the named account */
public FunnyMoney withdraw(String name, String password, int amount)
throws RemoteException, BankingException;
/** Return the amount of money in the named account */
public int getBalance(String name, String password)
throws RemoteException, BankingException;
/**
* Return a List of Strings that list the transaction history
* of the named account
**/
public List getTransactionHistory(String name, String password)
throws RemoteException, BankingException;
}
/**
* This simple class represents a monetary amount. This implementation
* is really nothing more than a wrapper around an integer. It is a useful
* to demonstrate that RMI can accept arbitrary non-String objects as
* arguments and return them as values, as long as they are Serializable.
* A more complete implementation of this FunnyMoney class might bear
* a serial number, a digital signature, and other security features to
* ensure that it is unique and non-forgeable.
**/
public static class FunnyMoney implements java.io.Serializable {
public int amount;
public FunnyMoney(int amount) { this.amount = amount; }
}
/**
* This is a type of exception used to represent exceptional conditions
* related to banking, such as "Insufficient Funds" and "Invalid Password"
**/
public static class BankingException extends Exception {
public BankingException(String msg) { super(msg); }
}
/**
* This class is a simple stand-alone client program that interacts
* with a RemoteBank server. It invokes different RemoteBank methods
* depending on its command-line arguments, and demonstrates just how
* simple it is to interact with a server using RMI.
**/
public static class Client {
public static void main(String[] args) {
try {
// Figure out what RemoteBank to connect to by reading a system
// property (specified on the command line with a -D option to
// java) or, if it is not defined, use a default URL. Note
// that by default this client tries to connect to a server on
// the local machine
String url = System.getProperty("bank", "rmi:///FirstRemote");
// Now look up that RemoteBank server using the Naming object,
// which contacts the rmiregistry server. Given the url, this
// call returns a RemoteBank object whose methods may be
// invoked remotely
RemoteBank bank = (RemoteBank) Naming.lookup(url);
// Convert the user's command to lower case
String cmd = args[0].toLowerCase();
// Now, go test the command against a bunch of possible options
if (cmd.equals("open")) { // Open an account
bank.openAccount(args[1], args[2]);
System.out.println("Account opened.");
}
else if (cmd.equals("close")) { // Close an account
FunnyMoney money = bank.closeAccount(args[1], args[2]);
// Note: our currency is denominated in wooden nickels
System.out.println(money.amount +
" wooden nickels returned to you.");
System.out.println("Thanks for banking with us.");
}
else if (cmd.equals("deposit")) { // Deposit money
FunnyMoney money=new FunnyMoney(Integer.parseInt(args[3]));
bank.deposit(args[1], args[2], money);
System.out.println("Deposited " + money.amount +
" wooden nickels.");
}
else if (cmd.equals("withdraw")) { // Withdraw money
FunnyMoney money = bank.withdraw(args[1], args[2],
Integer.parseInt(args[3]));
System.out.println("Withdrew " + money.amount +
" wooden nickels.");
}
else if (cmd.equals("balance")) { // Check account balance
int amt = bank.getBalance(args[1], args[2]);
System.out.println("You have " + amt +
" wooden nickels in the bank.");
}
else if (cmd.equals("history")) { // Get transaction history
List transactions =
bank.getTransactionHistory(args[1], args[2]);
for(int i = 0; i < transactions.size(); i++)
System.out.println(transactions.get(i));
}
else System.out.println("Unknown command");
}
// Catch and display RMI exceptions
catch (RemoteException e) { System.err.println(e); }
// Catch and display Banking related exceptions
catch (BankingException e) { System.err.println(e.getMessage()); }
// Other exceptions are probably user syntax errors, so show usage.
catch (Exception e) {
System.err.println(e);
System.err.println("Usage: java [-Dbank=<url>] Bank$Client " +
"<cmd> <name> <password> [<amount>]");
System.err.println("where cmd is: open, close, deposit, " +
"withdraw, balance, history");
}
}
}
}
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